The present invention relates to a method of manufacturing or constructing a ceramic refractory plate assembly for use in a sliding closure unit, the assembly being of the type including a plate-shaped refractory member having therethrough at least one discharge opening and a metal jacket surrounding the circumferential or peripheral edge of the refractory member. Assemblies of this type are widely employed in sliding closure units for regulating the discharge of molten materials, particularly molten steel.
DE-OS No. 31 08 748 discloses a refractory plate assembly of this general type wherein the refractory plate or member is connected to the sheet metal jacket or ring (in this instance the jacket includes a bottom surface) by a layer of refractory mortar. However, construction of an assembly employing mortar is an expensive operation. In addition, there exists the danger that the layer of mortar will not always be able to withstand the stresses which occur when the assembly is clamped in a metal support frame of a sliding closure unit and during sliding movements thereof.
It also is known that the metal jacket can be applied by shrinking a heated ring onto the peripheral edge of the refractory plate, or by applying the jacket in the form of a multilayer wound strip directly onto the circumference or periphery of the refractory plate. In both of these methods however, considerable variations of the dimensions of the refractory plates, arising from the manufacture thereof, are directly transferred to the outer dimensions of the metal jacket, and thus to the entire refractory plate assembly. In other words, exterior dimensional variations inevitably occur in the manufacture of the refractory plate-shaped members, and these dimensional variations are incorporated into the metal jackets applied by these operations. Therefore, it is necessary to provide either extensive further processing of the refractory plates before the jackets are fitted thereon and/or to provide subsequent machining of the exterior surfaces of the jackets, to ensure that the assemblies can be properly inserted and fit into, in an interchangeable manner, the respective support frames of the sliding closure units.
DE-OS No. 32 23 181 discloses a sheet metal ring in the form of a tension band fitted to a refractory plate by means of a tension jack. The tension band and tension jack form a device for fastening the refractory plate in its support frame, whereby the tension jack also must be worked or machined for the above discussed reasons. This publication discloses another arrangement wherein a metal ring is loosely positioned around a refractory plate and functions as part of the fastening device by being pressed in and deformed into lateral recesses in the plate by screws mounted on the support frame after the plate has been positioned therein. This type of arrangement wherein the plate is fastened in the support frame however is complicated and does not satisfactorily meet the desirable features of providing a properly seated and removable connection.